1. Field of the Invention
The present invention relates to a semiconductor memory system, and more particularly relates a non-volatile semiconductor memory system and a data writing method for writing data in the semiconductor memory system.
2. Description of the Related Art
As non-volatile semiconductor memories, NAND or NOR flash memories are known. The NAND flash memory includes so-called an ECC (error checking and correcting) which applies error detection and correction to write data and read data to enhance data reliability (see, for example, Japanese Patent Application Laid-Open No. 2012-133843). In data writing with the ECC, an encoding process for error correction is applied to a series of input write data pieces in one page unit corresponding to a plurality of memory cells connected to each word line. The encoded data for each page obtained by the encoding process is written to a memory cell array. During data reading, error correction is applied to the encoded data read in the page unit, and the error-corrected data is output as read data.